We call that style of tiling 'subway'. Those have very narrow or no visible grout lines, and would make this panel near invisible, not to mention perfect camouflage. Who expects a tiled wall can be opened?

Sincerely,
Toolmaker51
...we'll learn more by wandering than searching...

To make the panel tiles flush with the wall tiles, they have to make up for the depth of the mortar too. The fragility of the overhanging 1/2 tiles is questionable, but if this is just an access panel that gets opened maybe once a year, it's reasonable.

Real-world use could be an access panel for the inside of a firewood pass-through, via wall tiles on a hearth. Needs to be a bit beefier for daily use though.